Born in Phez in the Magrab (1051-29 April, 1025), he served as head of the Jewish courthouse. It seems that he won his position amongst the geonim of Eretz Israel thanks to his good schooling. He was a poet � some of his poems survived in the Cairo geniza. He wrote mostly in Hebrew, though also in Arabic. He is renowned thanks to two fierce debates: one concerning the kasherut of the Karaties� shops � the Fatimids interfered on this one and ceased the gaon; the second was with the gaon Natan b. Avraham, concerning power an appointments in the Jewish institutions.